In recent years, use of secondary batteries such as lithium ion batteries has rapidly expanded to power storage devices, automobile batteries and the like combined with new energy systems such as solar batteries and wind power generation. A battery system with one or a plurality of power storage devices connected is used. The power storage device is formed by putting one or a plurality of battery blocks into an armoring case. The battery block is formed by connecting a plurality of unit batteries (referred to as single battery or cell as well. In the ensuing description, the unit battery is referred to simply as battery cell as the occasion may demand), which are an example of power storage elements.
In Patent Literature 1 to Patent Literature 5 stated below, technologies relating to power storage devices are disclosed.